Recently, enhancement to support the Dedicated Core Network has been studied by 3GPP (3rd Generation Partnership Project).
The Dedicated Core Network intends that for example, a specific type of subscriber (i.e., a specific type of UE) is redirected to an MME (Mobility Management Entity)/SGSN (Serving GPRS (General Packet Radio Service) Support Node) dedicated to serve that UE. The Dedicated Core Network is also sometimes referred to as “Specific Core Network” or “Overlay Core Network”.
NPL 1 discloses the most prompting message flow to realize the Dedicated Core Network. In this message flow, when a UE sends an Attach Request message to new MME through an eNB (evolved Node B) (i.e., in a case of IMSI (International Mobile Subscriber Identity) attach), the one MME obtains information to use another specific MME from an HSS (Home Subscriber Server). Then, the one MME instructs the eNB to redirect the Attach Request message to the specific MME. Upon the redirection, the eNB performs the Attach procedure again to the specific MME.
NPL 2 also discloses a message flow similar to that disclosed in NPL 1.